Tool-carrier with adjustable pre-determined axial travel

ABSTRACT

The invention is concerned with tool-carrier devices having a variable pre-determined axial travel, of the type currently employed in the aeronautical industry in particular, for milling housings in metal sheets to a pre-determined axial depth, for receiving rivet heads for example. In one of the improvements of the invention, between the body and the sheath of the toolcarrier is interposed an intermediate sleeve which is keyed axially on the body and rotatable with respect thereto, the sheath being movable axially with respect to the sleeve but being keyed angularly on the sleeve. This definite separation of the movements of translation and rotation reduces wear in the moving parts and improves the precision. In a further improvement, the thrust-bearing is provided with a freely rotatable annular supporting ring mounted on and projecting from the free extremity of the bearing, thus eliminating contact of the tool-carrier with the surface to be machined and protecting this surface from damage by the tool-carrier.

United States Patent Bouzounie [451 Sept. 5, 1972 [54] TOOL-CARRIER WITH ADJUSTABLE PRE-DETERMINED AXIAL TRAVEL [72] Inventor: Lucien Bouzounie, Pontault-Combault, France [73] Assignee: Etablissements Recoules & Fils In- [58] Field of Search....408/72, 85, 86, 110, 112, 202, 408/180, 239; 308/DIG. 7

[56] References Cited UNITED STATES PATEN'IS 3,017,791 l/1962 Fried ..408/180 2,383,854 8/ 1945 Gwinn et a1. ..408/112 3,060,772 10/ 1962 Crump ..408/1 12 2,848,912 8/ 1958 Kalat ..408/112 3,120,982 2/ 1964 Leblanc ..308/DIG. 7 757,950 4/1904 McElwain et al ..408/112 2,242,510 5/1941 Cogsdill ..408/1 12 2,663,203 12/1953 Fried et al. ..408/72 2,905,030 9/ l 959 Cogsdill ..408/1 12 FOREIGN PATENTS OR APPLICATIONS 560,507 4/1944 Great Britain ..408/202 Primary ExaminerGerald A. Dost Attorney-Young & Thompson [57] ABSTRACT The invention is concerned with tool-carrier devices having a variable pre-determined axial travel, of the type currently employed in the aeronautical industry in particular, for milling housings in metal sheets to a pre-determined axial depth, for receiving rivet heads for example. In one of the improvements of the invention, between the body and the sheath of the tool-carrier is interposed an intermediate sleeve which is keyed axially on the body and rotatable with respect thereto, the sheath being movable axially with respect to the sleeve but being keyed angularly on the sleeve. This definite separation of the movements of translation and rotation reduces wear in the moving parts and improves the precision. In a further improvement, the thrust-bearing is provided with a freely rotatable annular supporting ring mounted on and projecting from the free extremity of the bearing, thus eliminating contact of the tool-carrier with the surface to be machined and protecting this surface from damage by the tool-carrier.

3Claims,3Drawing Figures PAIENTEBSEPBIQR I 3.689.171

//v VE/V role Zuc/E/v Bouz s TOOL-CARRIER WITH ADJUSTABLE PRE- DETERMINED AXIAL TRAVEL The present invention relates to tool-carriers with a variable pre-determined axial travel, of the type currently employed, in particular in the aeronautical industry for milling housings in metal sheets to a predetermined axial depth, for receiving rivet heads, for example.

Tool-carriers of this kind most frequently comprise a cylindrical body, a rotatable tool-carrier sheath movable axially inside the said body over a constant limited travel, a driving shaft coupled for rotation to the said sheath and intended to be coupled to the output shaft of a driving device, and an abutment or thrust device carried by the said body and adjustable in axial position on the said body.

After the desired adjustment of this thrust device, it is applied against the surface to be worked and the toolcarrier sheath passes into the body which surrounds it, during the course of milling, until the possible axial travel of this sheath has been fully utilized.

The present invention has for its object improvements in tool-carriers of this type. v

In tool-carriers of this kind known at the present time, the limitation of the axial travel of the tool-carrier sheath in the body which surrounds it is ensured by a ball thrust-bearing and this sheath, which is movable axially inside the body, is rotatably mounted directly in this latter. Due to these two combined movements of axial translation and rotation, the effects of which it absorbs directly, the ball thrust-bearing in question is rapidly subjected to non-negligible wear which adversely affects both the precision of the apparatus, since the length of the axial travel of the tool-carrier sheath will depend on this wear, and also its life.

According to one of the improvements of the present invention, between the body of the apparatus and the tool-carrier sheath is interposed an intermediate sleeve which is keyed axially on the said body and which is rotatable with respect to this latter, the said sheath being movable axially with respect to the said sleeve but being keyed angularly on this sleeve.

This arrangement advantageously results in a definite separation of the two movements in question, on the one hand the rotation which takes place solely between the body and the intermediate sleeve, and on the other hand the axial translation movement which takes place solely between the intermediate sleeve and the toolcarrier sheath.

This results in straightforward working of the parts concerned, and especially of the ball thrust-bearing by which the intermediate sleeve is fixed axially on the body, and thus ensures longer life of these parts together with improved accuracy of working of the apparatus.

Furthermore, in the tool-carriers known at the present time, the supporting thrust device of the apparatus is directly applied against the surface to be worked. Now, during operation, and particularly due to the inevitable internal friction, the body of the apparatus is subjected to a driving torque applied by the tool-carrier sheath. In consequence, if the said body is not suitably keyed for rotation, or if it accidentally escapes from any possible device which is intended to prevent it from rotating, the supporting thrust-bearing which is fixed on this body and which bears against the surface to be worked, begins to rotate, thereby causing this surface to be scored in an undesirable manner.

In accordance with a further improvement of the invention, the said thrust-bearing carries as a projection from its free extremity an annular supporting ring which is freely rotatable.

It is by this supporting ring that the tool-carrier comes into contact with the surface to be worked, so

I that even if it begins to rotate, the supporting ring which is held fixed for rotation by the said surface, protects the latter from damage of any kind.

Other objects, characteristic features and advantages of the invention will further be brought out in the description which follows below by way of example, reference being made to the accompanying drawings, in which:

One-half of FIG. 1 is a half-view in axial section of the tool-carrier according to the invention, while the other half is a half-view in elevation of the same toolcarrier;

FIGS. 2 and 3 are partial views in transverse section, taken respectively along the line II-II and the broken line III-Ill of FIG. 1.

According to the form of embodiment chosen and shown in these drawings, the tool-carrier according to the invention comprises the body 10, of which the lower section 11 of smaller diameter is threaded and has a longitudinal groove 12 on its surface.

In a manner known per se, on this threaded section 11 of the body 10 are engaged by screwing, on the one hand a locking ring-nut 13, at the upper portion of the said section, and on the other hand a thrust-bearing 14 at the lower portion of the said section, with the interposition of a vemier 15 between the said ring and the said bearing. This vernier carries a transverse stud l6 engaged in the groove 12 of the body 10, so that it is locked in rotation on the said body; it is further provided with an annular series of teeth 17 in engagement with corresponding teeth 18 carried by the upper edge of the thrust-bearing 14. A spring 20 is further interposed between the locking ring 13 and the vernier 15 in order to urge this latter in the direction of the bearing 14.

This thrust-bearing 14 is extended downwards beyond the body 10 by a skirt 21 having cut-away portions 22.

On the free extremity of this skirt 21 is screwed a ring 23 which abuts against the free edge of the said extremity and forms with this latter a housing 24. In this housing 24, a supporting ring 25 is mounted freely in rotation, this ring projecting beyond the ring 23.

This rotatable supporting ring 25, which forms one of the characteristic features of the present invention, is preferably made of any appropriate friction material such as those sold for example under the commercial names of TEFLON, NYLON," CELORON or the like. It is provided with a flange 26 which is engaged in the housing 24 and by which it is thereby retained. The axial height of this flange 26 is obviously less than the corresponding axial height of the housing 24 in order that the supporting ring 25 may be free to rotate.

In the example shown, the flange 26 has a substantially rectangular section, but it is understood that this section may be different and may in particular be triangular, the flange 26 then having a conical shape.

According to a second characteristic feature of the invention, an intermediate sleeve 30 is rotatably mounted in the body 10, while being keyed axially on this body. its axial retention is ensured on the one hand by a ball thrust-bearing 31 interposed between a transverse shoulder 32 of the body and a transverse shoulder 33 of the sleeve 30, and on the other hand by a locking washer 35 held in contact with the lower edge of the body 10 by a circlip 36 or any other elasticallydeformable split washer anchored in a groove 37 in the lower portion of the sleeve 30.

Between the body 10 and the intermediate sleeve 30 are arranged two needle-bearings 38, 39, axially staggered on each side of the ball thrust-bearing 31.

Thus, according to the invention, the intermediate sleevel30 is keyed axially in the body 10 and can only rotate in the said body.

At the upper portion of the intermediate sleeve 30 is screwed an annular retaining plug 40, the internal periphery 41 of which is of conical shape, flared towards the interior and provided externally with a flange 42 covering the annular space which exists between the body 10 and the sleeve 30 for the housing of the needle-bearing 38.

Inside the intermediate sleeve 30 is arranged an axially-movable tool-carrier sheath 45, the lower part of which is provided with an internally-threaded portion 46 for mounting a tool in position, and comprises externally a longitudinal groove 47. In this groove is engaged a stud 48 provided radially on the lower portion of the intermediate sleeve 30, so that the tool-carrier sheath 45 is keyed for rotation on this intermediate sleeve 30 according to the invention.

Between the sheath 45 and the intermediate sleeve 30 is interposed axially a spring 50, which is supported on the one hand by an internal transverse shoulder 51 of the sleeve 30, and on the other hand by an internal transverse shoulder 52 of the sheath 45.

On the sheath 45 a driving shaft 55 is keyed for rotation, this shaft having a frusto-conical bearing surface 56 intended to co-operate in abutment with the frustoconical bearing surface 41 of the retention plug 40.

According to the form of embodiment illustrated, the fixing together for rotation of the shaft 55 and the toolcarrier sheath 45 is effected by swivel-joint means comprising a spherical surface 60 formed at the extremity of the shaft 55, a conical surface 6] formed on the inner surface of the sheet 45 for co-operation with the said spherical surface 60, a port 63 passing straight through the shaft 55, this port being elongated axially in height, and a shaft 64 transversely fixed on the v sheath 45 and arranged in the port 63.

As will be readily understood, this arrangement provides a certain inclination for the shaft 55 in any I direction, when the conical surfaces 41 and 56 are not in engagement, this inclination being with respect to the axis of the sheath 45, and therefore with respect to the axis of the tool-carrier.

Finally, the intermediate sleeve 30 also comprises on its internal surface, between its shoulder 51 and the shoulder 52 of the sheath 45, a transverse shoulder 65 intended to co-operate with the said shoulder 52 of the sheath 45.

In service, the driving shaft 55 is coupled for rotation to the output shaft of a motor and a tool is in position in the sheath 45, in the threaded portion 46 of this latter (not shown). The spring 50 urges the sheath 45 upwards, and with it the shaft 55, this shaft 55 being driven by the sheath 45 due to their respective contact surfaces and 61. The bearing surface 56 of the shaft 55 is from then on in abutment against the bearing surface 41 of the retention plug 40. Due to the conicity of these bearing surfaces, the tool carrier is perfectly centered with respect to the shaft 55 and its setting into operation does not therefore cause any out-of-balance.

in this waiting position, which is that shown, the distance separating the shoulders 52 and is C; this distance defines the maximum possible axial travel of the sheath 45 in the body 10. Furthermore, in this waiting position, the tool shown partly in a diagrammatic manner in broken lines in FIG. 1, is set back inside the skirt 21 of the thrust-bearing 24, and is separated from the front of the supporting abutment 25 by a distance J. This distance J is variable at will, in a manner known per se, by screwing or unscrewing the vernier 15 with respect to the body 10, with a prior adjustment of the locking ring-nut l3.

The tool-carrier is brought into application against the surface to be worked; as this application is effected according to the invention through the intermediary of the supporting ring 25, the said surface runs no risk of damage.

The sheath 45 is then pushed into the body 10 until the shoulders 52, 65 come into abutment. This abutment is definite and the penetration of the tool 70 into the surface to be worked is also clearly defined, being obviously equal to C-J.

It will be understood that the present invention is not limited to the form of embodiment described and illustrated, but includes any alternative form of construction. in particular, the driving shaft 55 could be keyed directly on the tool-carrier sheath 45 without the interposition of any swivel means of any kind.

I claim:

1. In a toolcarrier with an adjustable predetermined axial travel, comprising a body, a rotatable tool carrier sheath movable axially in said body along a constant limited path of travel, a driving shaft coupled for rotation to said sheath, and a thrust device carried externally by said body and adjustable axially in position on said body; the. improvement comprising an intermediate sleeve disposed between said body and said sheath, said sleeve'being keyed axially on the body and freely rotatable with respect to the body, said sheath being movable axially relative to said sleeve but keyed angularly on said sleeve, said body and said intermediate sleeve having transverse shoulders facing each other, a ball thrust bearing disposed between said transverse shoulders, and two needle bearings between said body and said sleeve disposed one on each side of said shoulders.

2. A tool carrier as claimed in claim 1, one of said sleeve and body having at one of its extremities an annular groove, an elastically deformable open ring of the circlip type disposed in said groove, and a locking washer in contact with the corresponding extreme edge of the other of said sleeve and body and retained by said open ring.

3. in a tool carrier with an adjustable predetermined axial travel, comprising a body, a rotatable tool carrier being movable axially relative to said sleeve but keyed angularly on'said sleeve, said sleeve having at its upper portion an annular retention plug the internal periphery of which is frusto-conical and flared toward the interior, said driving shaft having a coaxial frustoconical bearing surface for abutment against said retention plug.

' a: a: a n a- 

1. In a tool carrier with an adjustable predetermined axial travel, comprising a body, a rotatable tool carrier sheath movable axially in said body along a constant limited path of travel, a driving shaft coupled for rotation to said sheath, and a thrust device carried externally by said body and adjustable axially in position on said body; the improvement comprising an intermediate sleeve disposed between said body and said sheath, said sleeve being keyed axially on the body and freely rotatable with respect to the body, said sheath being movable axially relative to said sleeve but keyed angularly on said sleeve, said body and said intermediate sleeve having transverse shoulders facing each other, a ball thrust bearing disposed between said transverse shoulders, and two needle bearings between said body and said sleeve disposed one on each side of said shoulders.
 2. A tool carrier as claimed in claim 1, one of said sleeve and body having at one of its extremities an annular groove, an elastically deformable open ring of the circlip type disposed in said groove, and a locking washer in contact with the corresponding extreme edge of the other of said sleeve and body and retained by said open ring.
 3. In a tool carrier with an adjustable predetermined axial travel, comprising a body, a rotatable tool carrier sheath movable axially in said body along a constant limited path of travel, a driving shaft coupled for rotation to said sheath, and a thrust device carried externally by said body and adjustable axially in position on said body; the improvement comprising an intermediate sleeve disposed between said body and said sheath, said sleeve being keyed axially on the body and freely rotatable with respect to the body, said sheath being movable axially relative to said sleeve but keyed angularly on said sleeve, said sleeve having at its upper portion an annular retention plug the internal periphery of which is frusto-conical and flared toward the interior, said driving shaft having a coaxial frusto-conical bearing surface for abutment against said retention plug. 